change(ci): Fail CI if there are doc warnings (#5683)

* Fail CI if there are doc warnings

* Try a different syntax

* Use an env var

* Fix spacing, add reference

* Allow intra-doc links

* Note that rustdoc settings need to stay in sync

.cargo/config.toml

@@ -36,10 +36,9 @@ rustflags = [
     "-Wclippy::unnecessary_cast",
 
     # Incomplete code
-    "-Wmissing_docs",
     "-Wclippy::dbg_macro",
     "-Wclippy::todo",
-
+    
     # Manual debugging output.
     # Use tracing::trace!() or tracing::debug!() instead.
     "-Wclippy::print_stdout",
@@ -49,12 +48,18 @@ rustflags = [
     # Code styles we want to accept
     "-Aclippy::try_err",
 
-    # Links in public docs can point to private items.
-    "-Arustdoc::private_intra_doc_links",
-
     # Panics
     "-Wclippy::fallible_impl_from",
     "-Wclippy::unwrap_in_result",
+    
+    # Documentation
+    "-Wmissing_docs",
+
+    # These rustdoc -A and -W settings must be the same as the RUSTDOCFLAGS in:
+    # https://github.com/ZcashFoundation/zebra/blob/main/.github/workflows/lint.yml#L152
+    
+    # Links in public docs can point to private items.
+    "-Arustdoc::private_intra_doc_links",
 
     # TODOs:
     # `cargo fix` might help do these fixes,

.github/workflows/lint.yml

@@ -143,6 +143,13 @@ jobs:
     runs-on: ubuntu-latest
     needs: changed-files
     if: ${{ needs.changed-files.outputs.rust == 'true' }}
+    # cargo doc doesn't support '--  -D warnings', so we have to add it here
+    # https://github.com/rust-lang/cargo/issues/8424#issuecomment-774662296
+    #
+    # These -A and -W settings must be the same as the rustdoc settings in:
+    # https://github.com/ZcashFoundation/zebra/blob/main/.cargo/config.toml#L53
+    env:
+      RUSTDOCFLAGS: -D warnings -A rustdoc::private_intra_doc_links
 
     steps:
       - uses: actions/checkout@v3.1.0